A main halyard should have a low elongation. This is required for properly trimming your sail: when the wind increases, you want your main sail to stay flat. For Dinghy recreational we recommend the ropes below.
This high quality performance regatta rope, has a Stirotex grade 12 coated core and 24 braid HT Polyester cover. Features: Suitable for splicing and tapering, very low stretch, light weight, great durability, stronger than steel. Especially suitable for halyards and sheets.